Nowadays, fluid transportation devices used in many sectors such as pharmaceutical industries, computer techniques, printing industries, energy industries are developed toward miniaturization. The fluid transportation devices used in for example micro pumps, micro atomizers, printheads or industrial printers are very important components. Consequently, it is critical to improve the fluid transportation devices.
FIG. 10A is a schematic cross-sectional view illustrating a conventional micro pump in a non-actuation status. The conventional micro pump 8 comprises an inlet passage 83, a micro actuator 85, a transmission block 84, a diaphragm 82, a compression chamber 811, a substrate 81 and an outlet passage 86. The compression chamber 811 is defined between the diaphragm 82 and the substrate 81 for storing a fluid therein. Depending on the deformation amount of the diaphragm 82, the capacity of the compression chamber 811 is varied.
When a voltage is applied to electrodes disposed on opposite sides of the micro actuator 85, an electric field is generated. In response to the electric field, the micro actuator 85 is subjected to a downward deformation. Consequently, the micro actuator 85 is moved toward the diaphragm 82 and the compression chamber 811. Since the micro actuator 85 is disposed on the transmission block 84, the pushing force generated by the micro actuator 85 is transmitted to the diaphragm 82 through the transmission block 84. In response to the pushing force, the diaphragm 82 is subjected to a compressed deformation. Please refer to FIG. 10B. The fluid flows in the direction indicated as the arrow X. After the fluid is introduced into the inlet passage 83 and stored in the compression chamber 811, the fluid within the compression chamber 811 is pushed in response to the compressed deformation. Consequently, the fluid will flow to a predetermined vessel (not shown) through the outlet passage 86. In such way, the fluid can be continuously supplied.
FIG. 10C is a schematic top view of the micro pump shown in FIG. 10A. When the micro pump 8 is actuated, the fluid is transported in the direction indicated as the arrow Y. The micro pump 8 has an inlet flow amplifier 87 and an outlet flow amplifier 88. The inlet flow amplifier 87 and the outlet flow amplifier 88 are cone-shaped. The larger end of the inlet flow amplifier 87 is connected to the inlet passage 831. The smaller end of the inlet flow amplifier 87 is connected to the compression chamber 811. The outlet flow amplifier 88 is connected with the compression chamber 811 and the outlet passage 861. The larger end of the outlet flow amplifier 88 is connected to the compression chamber 811. The smaller end of the outlet flow amplifier 88 is connected to the outlet passage 861. In other words, the inlet flow amplifier 87 and the outlet flow amplifier 88 are connected to the two ends of the compression chamber 811. The inlet flow amplifier 87 and the outlet flow amplifier 88 tapered off in the same direction. Due to the different flow resistances at both ends of the flow amplifiers, and the volume expansion/compression of the compression chamber 811, a unidirectional net mass flow rate is rendered. That is, the fluid flows from the inlet passage 831 into the compression chamber 811 through the inlet flow amplifier 87 and then flows out of the outlet passage 861 through the outlet flow amplifier 88.
However, this valveless micro pump 8 still has some drawbacks. For example, a great amount of the fluid is readily returned back to the input channel when the micro pump is in the actuation status. For enhancing the net mass flow rate, the compression ratio of the compression chamber 811 should be increased for reaching a sufficient chamber pressure. Under this circumstance, a costly micro actuator 85 is required.
For solving the drawbacks of the conventional technologies, the present disclosure provides a fluid transportation device for maintaining the working performance and the flowrate of the fluid.